When a wire carrying an electric current is moved in a magnetic field
of a magnet the magnetic field induced by the wire reacts with the magnetic
field of the magnet causing the wire to move outwards. Fleming's left
hand rule helps you to predict the movement.

First finger - direction of magnetic field (N-S)

SeCond finger - direction of current (positive to negative)

ThuMb - movements of the wire

When a coil of wire carrying a current is placed in a magnetic field the coil
turns.

This is called the motor effect.

The Practical Applications of this Theory

By using the three components:

electricity

magnetism

movement

and the coil of the electro-magnet, a wide range of practical applications
are possible.

Electric motors have magnets, a coil, and use electricity to produce
movement.

The magnet fieldof the coil pushes away from the magnetic field in
the surrounding magnet, so turning the coil and the motor spindle.

Dynamos - use magnets, a coil and movement to produce electricity in
exactly the opposite way to the motor. Small electric motors can be used as
dynamos, especially for such things as a model wind generator. Connect a propellor
to the motor and a voltmeter to the motor wires. Blow on the propeller and watch
the voltage go up.

Loudspeakers use electricity, a coil
and a magnet to make the speaker
cone move.

Microphones can work in the opposite
way using movement caused by sound waves together with a coil and magnet
to produce electricity - which then travels
along a wire, usually via an amplifier,
to a loudspeaker which ........

Other practical applications of the electro-magnetic effect are:

transformers

electric bells

relay switches

and Mag-lev trains - but you can find out more about those if you are really
interested.